镍团簇的结构与电子性质

Geometrical Structure and Electronic Properties of Small Nickel Clusters

在相对论有效原子实势(RECP)近似下,用Gaussian98程序和密度泛函中的B3LYP/LANL2DZ方法,对纯Nin(n=2-6)团簇的各种几何构型进行优化计算,得到它们的基态结构、垂直电离势和电子亲和能。结果表明,Ni2分子的基电子态为3Σu+,Ni3的基态结构是等腰三角形,电子态为3B2。由于Jahn-Teller效应,Ni4的基态结构为具有C2v对称性的蝶形结构,电子态为7A2。Ni5和Ni6的基态结构也具有C2v对称性,分别为梯形和三角形结构,对应的基电子态分别为7A1和3B2。最后计算了团簇的能级分布和最高占据轨道(HOMO)与最低空轨道(LU-MO)之间的能级间隙(HLG),分析了团簇的化学活性。

The possible geometrical and electronic structures of the Ni, （n = 2-6） clusters are optimized by density functional theory（DFT） method with relativistic effective core potential（RECP） using Gaussian 98 code with the LANL2DZ basis set. The ionization potentials and electron affinities of Nin clusters, with n = 2-6, are also probed in this study. The results obtained indicate that the ground electronic state is ^3∑u^＋ for Ni2. The ground state configuration of Ni3 cluster is an isosceles triangle with C2, symmetry in 3B2 electronic state. Due to the Jahn-Teller effect, the present calculations for Ni4 obtain a butterfly-like ground state with C2v symmetry in the 7A2 electronic state. Both clusters, Ni5 and Ni6, are of C2v symmetry, and the ground electronic state of Ni5 and Ni6 is ^7A1 and ^3B2 respectively. Finally, the energy level distributions, HOMO-LUMO gaps and the chemical activation are investigated.